Superman was never previewed because the producers didn't trust Warners with the film.
Imagination is everything. It is the preview of life's coming attractions.
Internet mailing lists are like Fox television shows. They have really cool previews and they get you all excited about them but they just don't live up to their promises.
I don't know much about auctions. I sometimes go to previews and see art sardined into ugly rooms. I've gawked at the gaudy prices and gaped at well-clad crowds of happy white people conspicuously spending hundreds of millions of dollars.